Shoe sewing machine



Dec; 28, 1943. B T LEVE UE 2,337,611

SHOE SEWING MACHINE Original Filed Aug. 17. 1940 2 Sheets-Sheet 2 E 5%: s &

I Q Q PE Ff GD I m illllllllllllllllIflllilllilill Patented Dec. 28, 1943 UNITED STAT s PATENT orrler SHOE SEWING MACHINE Bernard T. Leveque, Wenham, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey 6 Claims.

The present invention relates primarily to shoe sewing machines, and is herein disclosed as embodied in a curved hook needle lockstitch shoe sewing machine adapted to sew the outsole to the welt and upper of a welted shoe, the illustrated embodiment of the invention being similar in certain respects to the machine disclosed in the present inventors prior Patent No. 2,144,766 of January 24, 1939, and in therein referred to patents issued on divisional applications based on said patent.

An object of the invention is to provide a lockstitch sewing machine with a new and improved thread measuring mechanism whereby the proper amount of needle thread may be automatically rendered available for setting the stitch a uniform distance in the work regardless of the thickness thereof.

With this object in view, a feature of the invention involves the provision of needle thread measuring mechanism arranged to engage a portion of the thread carried by the take-up mechanism to control, with reference to the thickness of the work, the amount of thread drawn oif prior to i to those skilled in the art from the following L description.

An outsole shoe sewing machine embodying the several features of the present invention is illustrated in the accompanying drawings, in which Fig. 1 is a view in right-hand side elevation, partly in section, of the head of the machine illustrating particularly the train of mechanism for actuating the take-up; Fig. 2 is a detail View in right side elevation, partly in section, of the take-up mechanism of the machine, showing the thread measuring mechanism and the thread clamp, the take-up arms being shown in extended position for setting the stitch; Fig. 3 is a view in front elevation, partly in section, of the parts shown in Fig. 2, and taken on the line 33 of that figure; and Fig. 4 is a view taken similar to Fig. 2, but with the take-up arms together, showing the manner in which the thread measuring mechanism cooperates with the take-up mechanism in pulling off thread from the supply.

.The stitch forming and work handling devices adjacent the sewing point comprise, in the machine of the present invention, the work support 20, the presser foot 22, curved hook needle 24, curved awl 26, looper 2B, thread arm 30, loop spreader 32 and rotary shuttle 34. These parts are substantially similar in arrangement and mode of operation to those of the machine disclosed in the present inventors prior Patent No. 2,144,766 above referred to and in the patents issued on divisional applications based thereon.

The main shaft of the illustrated machine consists of a crank shaft 36 provided with a plurality of throws or cranks, each of which, by suitable connections, actuates a separate train of mechanism for driving the stitch forming or work handling device connected thereto. The individual cranks of the crank shaft 3% are connected to their various stitch forming and work handling devices through mechanisms which convert the simple crank motions into complex movements best adapted for actuating each device according to the characteristic motion desired. This is accomplished by the provision of members having cam slots within which are oscillated cam followers by connections to the respective cranks of the crank shaft, the configuration of the different cam slots being arranged in accordance with the requirements of the respective actuated devices.

The take-up mechanism is actuated from the crank (Fig. 1) at the left-hand end of the crank shaft 36, as viewed from the front. The crank is connected by link 62 to rock arm 64. pivotally mounted on cross shaft 44, the rock arm being provided at its outer end with a follower roll which is oscillated in an arcuate path along a cam slot in cam lever 63. The dwell portion of the cam slot is indicated at ill, while the actuation of the take-up occurs during the traverse by the roll of the inclined portion it, a brief dwell being provided at the upper end by the short arcuate portion M, in addition to that afforded by the passage of the crank throw over dead center.

The various stitch forming and work handling devices are actuated. from their respective cam levers through appropriate linkages. In order that the machine may be stopped quickly and without undue shock or jar, the linkages include elements arranged to be disconnected so that the devices may be stopped independently of the crank shaft, rock arms, and cam levers, as fully illustrated and described in applicants prior ap plication Serial No. 353,083, filed August 17, 1940, of which the present application is a division.

The stitch forming and work handling devices are actuated from their cam levers by mechanisms which include links disconnectibly onnected to the cam levers. The disconnectible link for the take-up mechanism is shown at H16 in Fig. l. The link is connected to one arm of a bell crank Hi8, the other arm of which has a toothed segment H intermeshing with gear H2 on one arm H4 of the take-up, the other arm I l 6 being driven through gear I IS.

The presser foot 22 is actuated to clamp and unclamp the work by means of Horton clutch. mechanism imilar to that fully illustrated and described in the inventors U. S. Letters Patent No. 2,098,298 of November 9, 1937. As in said: patent, the clutch is arranged to clamp the work upon rocking the inner member in counterclockwise direction. In the present machine, this rocking movement is effected by a lever l2!) secured to the shaft I22 upon which the inner or actuating member of the clutch is mounted. The outer or actuated member I24- is connected by link I26 to the bell crank lever Hi; to which the presser foot is secured. The lever l2!) is provided with a cam slot l3i] within which is reciprocated a. roll or follower l32 carried by an upward extension I 34 of a needle cam lever (not shown), similar to the take-up cam lever 68, but formed with a differently shaped cam slot to impart suitable movements to the needle. The parts are shown in Fig. 1 with the clutch in clamping position, the follower I32 being at the inner end of the, cam slot I36, while the clutch is released when the follower is at the outer end of the slot, as indicated by the dotted outline I36.

In order that the stitches may be set with the thread looks a uniform distance below the surface of the work regardless of variations in the thickness thereof, the machine of the present invention is provided with mechanism ar ranged to cooperate with the take-up, during the passage of the loop of needle thread over the shuttle, to measure in relation to the thickness of the work the amount of thread drawn off from the supply so that the proper length will be available for setting the stitch with the lock at the desired depth. The take-up mechanism, already referred to, is similar to that illustrated in the applicants Patent No. 2,097,462, dated November 2, 1937, in that the take-up arms I I4 and H6, in setting the stitch, are moved from a position in which they are substantially parallel (see Fig. 4), into a posit on of substantial alignment at the limit of their taking-up stroke, as shown in Figs. 1 and 3, with the result that the amount of thread taken up is unaffected by overthrow of the parts. During the take-up stroke, a thread clamp having fixed and movable gripping jaws 286 and 283, respectively, is caused to clamp the thread between the take-up and the supply, while during the upward movement of the thread loop over the shuttle, the thread clamp is opened to permit thread to be drawn from the supply as required.

The thread measuring mechanism for determing the amount of thread drawn off from the supply relative to the thickness of the work comprises a thread finger 290 adiustably secured by a set screw 2&2 (Fig. 3) in a bore in one end of a bar 294. The bar extends forwardly through the machine frame with the finger 298 located in' a position to engage the portion of the thread loop between the take-up arms when the latter are in parallel or retracted position, as in Fig. 4. The thread finger is positioned to draw aside more or less thread, and therefore cause to be pulled from the supply a greater or a lesser amount of thread, by connections controlled by the position of the presser foot when in clamping position. The bar 294 is slidably mounted in the machine frame and is connected at its rear end to one arm of a lever 296 by means of a short link 2913. The other arm of lever 298 is connected by a link Bill] to a lug 3512 on the outer clutch member I24 of the presser foot actuating mechanism. Since the angular position of member I24 when in clamping position is directly dependent on the thickness of the work engaged by the presser foot, the setting of the thread measuring finger 29B is likewise controlled by the work thickness. For thin work, when the presser foot is relatively close to the work support, the thread finger is in extended position, indicated by dotted line 304 in Fig. l, and thus has no appreciable effect on the amount of thread drawn off as the thread loop passes over the top of the shuttle. As the thickness of the work increases, the thread finger is moved inwardly so that the thread is engaged before the take-up arms reach fully retracted position, diverting the thread loop and thus causing additional thread to be pulled off from the supply in an amount which will permit the thread lock to be drawn the proper distance into the work when the stitch is set by the take-up.

The thread clamp is actuated to grip the thread during the setting of the stitch by means of a cam 306 on drive shaft I M, the cam having an axial cam slot 3118 in which is received a follower 3lll on a rock arm 3l2 pivotally mounted on the machine frame. The arm M2 is provided with a block 3% through which passes a reduced end portion of a bar 3N5 on which the movable gripping jaw 288 is mounted. A compression spring 318 provides a yielding connection between the shoulder on the bar and the arm 312 when the arm 3E2 is rocked in thread clamping direction.

The bar also carries at one end a pair of check nuts 32!] acting to retract the bar 3l6 when the arm 3l2 is rocked in the reverse direction.

The advantage of the illustrated thread measuring mechanism is in a construction in which no rapidly moving parts are required other than the take-up, the thread finger being moved by relatively small amounts corresponding to the movements of the presser foot and the take-up actually drawing the thread from the supply. As each stitch is being set, all of the measured thread is available, but while each needle loop is being passed over the shuttle, the measure ment takes place, the take-up bringing ie thread into engagement with the thread measuring finger 290. The take-up is at this time giving up thread so that no erratic movement occurs in the thread while the needle loop is passing over the shuttle. After the needle loop passes over the shuttle, the measured amount of needle thread becomes available and no thread guiding 'and friction increasing thread engaging members, in addition to the take-up and thread finger 29B, are needed to control the movements of the thread. Thus, an extremely efficient needle thread handling system results with a minimum possible number of thread engaging or controlling parts.

The nature and scope of the present invention having been indicated, and a machine embodying the several features of the invention having been specifically described, what is claimed is:

l. A lockstitch sewing machine having, in combination with the other stitch forming and work feeding devices including a presser foot and actuating mechanism for causing the presser foot to clamp and unclamp the work, take-up mechanism comprising thread engaging members, a thread measuring finger, means for actuating said thread engaging members to take up and give up thread during each stitch forming cycle and during the giving up movement to bring the thread into engagement with the thread measuring finger, and means controlled by the thickness of the work for adjusting the position .1

of the thread measuring finger.

2. A lockstitch sewing machine having, in combination with the other stitch forming devices, a take-up comprising two pivotally mounted arms, a thread guide on each arm, means for rocking the arms from a position of substantial parallelism to an aligned position to expand the loop 01 thread passing around the guides, and thread measuring mechanism acting on the thread loop between the thread guides of the take-up to draw ofi a length of thread determined by the thickness of the work.

3. A lockstitch sewing machine having, in combination with the other stitch forming devices, a

take-up comprising two pivotally mounted arms,

a thread guide on each arm, means for rocking the arms from a position of substantial parallelism to an aligned position to expand the loop of thread passing around the guides, and thread measuring means controlled by the thickness of the work for engaging and diverting a portion of the thread between the guides when the takeup arms are approaching parallelism with the thread loop in contracted position.

4. A lockstitch sewing machine having, in combination with the other stitch forming devices, a take-up comprising two pivotally mounted arms, a thread guide on each arm, means for rocking the arms from a position of substantial parallelism to an aligned position to expand the loop of thread passing around the guides, and means comprising a thread engaging finger positioned by connections from the presser foot mechanism to divert the thread loop carried by the take-up when the latter is in retracted position.

5. A lockstitch sewing machine having, in combination with the other stitch forming devices, take-up mechanism comprising members having thread guides for supporting a loop of thread thereon, means for actuating the members to cause alternate expansion and contraction of the thread loop while bodily displacing the same, a thread finger adapted to be engaged by a portion of the thread loop during displacement thereof towards contracted loop position, and means controlled by the thickness of the work for adjusting the position of the thread finger in the line of displacement of the loop to vary the amount of diversion of the thread by the finger when the take-up reaches contracted loop position.

6. A lockstitch sewing machine having, in combination with the other stitch forming and work feeding devices including a presser foot and actuating mechanism for causing the presser foot to clamp and unclamp the work, take-up mechanism arranged to alternately expand and contract a loop of thread to take up and give up the thread, said take-up comprising two pivotally mounted arms, thread guides on the arms, and means for rocking the arms from a position in which the arms are in substantial alignment to a position in which the arms are approximately parallel whereby, in contracting the thread loop the latter is bodily displaced, a thread finger adapted to be engaged by a portion of the thread loop during displacement thereof by the take-up toward contracted loop position, and means controlled by the thickness of the work for adjusting the thread finger transversely of the line of the thread between the thread guides, said adjusting means including connections actuated by the presser foot clamping mechanism.

BERNARD T. LEVEQUE. 

